A lone gunman with extreme rightwing sympathies has gone on a shooting spree in Florence, killing two Senegalese street vendors and wounding three others before killing himself.

Gianluca Casseri, 50, an accountant, first shot dead two vendors and wounded a third with a .357 Magnum at the crowded Piazza Dalmazia street market on the outskirts of the city on Tuesday morning.

He then fled in a car after threatening to shoot a stall holder who attempted to stop him, reappearing later in the day at the central San Lorenzo market where he fired at two African vendors, wounding both.

Police officers found Casseri back in his car in the car park of the market, where they fired warning shots before he reportedly shot himself dead.

Described as a solitary type who had recently moved to Florence from a small Tuscan town, Casseri was a fan of fantasy comics and fiction including Tolkien. Last year he published a historical novel.

The Italian far-right, anti-immigration organisation Casapound said on Tuesday that Casseri was a "sympathiser" who had frequented one of its centres in Tuscany, holding talks on his book.

Around 300 Africans marched in protest at the killings, demanding to see Casseri's corpse. "Don't tell us he was a madman," said one, "because if he was he would have killed whites as well as blacks".

A vendor at Piazza Dalmazia said: "Senegalese lads often sell here, they don't make any trouble and no one expected this."